Electronic counting and computing arrangements



J. R. ACTON Dec. 10, 1957 ELECTRONIC COUNTING AND COMPUTING ARRANGEMENTSInvenlor JOHN R. ACTON 5 21;

Filed July 19, 1956 I Attorneys United States Patent ELECTRONIC COUNTINGAND COMPUTING; ARRANGEMENTS John Reginald Acton, Beeston, Nottingham,England, assignor to .E'ricsson Telephones Limited Application July 19,1956, Serial N0; 598,856

priority, application Great Britain July 25; 1955 6;-Claims. (Cl.SIS-84.6)

The-present inventionrelates to. electronic: counting :and computingarrangements, and particularly; tosuch arrangementsv which include oneor more gaseousdischarge tubesa eacha containing-a plurality. ofelectrode; discharge points spaceda uniform distance apart'inaa-cringiaround andsequidistantfrom a common electrode.

It'is'an object-of my invention to' provide. improvedvolta'geestabilising arrangements forruse, and inrcombinatiomiwiththe:aforesaidzj-dischargectubeswwhichhare; forginstance; described inUnited Kingdom patent application Numberi1,32.4/ 49 (Serial. Number; 712,"17'1).-. Thisrpatent application-relates to. a discharge tuberhavingaaplurality 2,816,250 Patented Dec. 10, 1957 5 of the potentialthereatwithin a determinedrange of of cathode electrode discharge: points:disposediequidistantly-from: the discharge surface. of a commonlian'odeelectrode. In. such: a tube a discharge glow investing one:ofi;theeccatliodezdischarge points'is causedto' move-.10 anothercathode. discharges point by way of two .intermediate; guidei:"electrodes in response to each impulse 'of'theranode of such tubeisrprogressively reduced as the :number of disch'arges present in the:tube "increases; thus rendering unstable the value of the applied'potentials necessary, on the one hand, to produce furtherdischargesinxthestube, or, on the otherhand; to causethe existing discharg'estomove from onecath'ode to another. drawback's of the knownmulti-electrode discharge tubes :will besset-forth in greater detailfurther below.

Thisipresent invention is in the nature of 'animprovementon" the impulsecounting arrangements depicted The v andiidescri-bed in theaforesaidvpatent application Num- 1 her 32,0.72/53; and. overcomes theaforesaid drawback by providing inf-these arrangements means whereby thep0.-

ten-tial atf'the anode of a discharge tube containing aplurality ofcathodes is maintained automatically 'at 'a subst-antially constantvoltage without regard-to the number ofi' discharges existing in thedischarge tubeand' the corresponding variations in the loadtherein.

According to my invention I provide an arrangement for 'counting-andstoring electrical pulses comprisinga gaseous el'ectric discharge tubecontaining=an anode and aplurality of cathodes,- means for applying: a;pulse=to a cathodedn said discharge tube and storingit withi-n thedischarge tube in the form of a discharge between theanode and saidcathode, means forapplying a pulse to a plurality of cathodes in commonand thereby causing a'discharge to: move from one cathode to.anotherzcathode, meanswhereby. an impulse stored in the. tube initheform offazdischarge, is counted out from: saiditube impulse torm-,. in.combination. with anode potential. stabilizing :means,..whereb,yz a;potentiaLderii/ed from mired-current 1 .assembly as. described later.

values.

Againaccording to myinvention I provide voltage stabilisingarrangements. for use with a variable load whereinaUpotential-derived.from a direct current, source is applied toan-ianodeof a thermionicvalve, and-,a cathode. ofv said, valve is. connected to acathode follower circuit, and wherein a: potential;at thelload isderived from said cathode of saidpvalvev and is maintained automaticallyat-a.value:within adeterminedrange of *values without regard to thevalue of the loadcurrent.

The. presentv invention .will now. be. more. fully describedWithreference tojthe accompanying. drawing which shows a-. .simpleembodiment of. my invention. Inthis. simple circuitarrangementI.provide. a gaseous discharge tube DTD. in whichthe discharge points ofthirty electrodes are spaced a@ uniform ,distanceapart and arrangedin 1aring;,around the dischargesurface, of a circular anode-A common. to}the, said. thirty electrodes; One or more auxiliary electrodes-maytalsobe provided and be situated in suitable: positions. with respect to themainvelectrode Each. electrode. in .the. tube DIDfis providedwithseparate meansof accessfrom the containing bulb or envelope; Threehalf-waverectifying valves DIA, DIB.,. and DT C, with-a thermionictriodevalvetDTErarealso included in the depicted arrangement. Forthe. purposeof .this description, ten of the;sai,d..thri ty electrodesjintubeDTD.will be termed cathodes and designateduTltto T10, ,a further.v ten. willbevvtermedwfirst guide. electrodes/and designated GA'1. to" GA10,andsthe remaininggtenQwill betermedsecond guideelectmdesand designatedGB'1-to, GB'10.. When so termed,the,saidithirty electrodes, of. whichapart only-areshown symbolically, are'jarr'anged. around'anode A invtheorder cathode. T1, first a guide we GA1,. second guidev (3B1, cathodeT2,' and.- so

on in the same order withsecond guideGBIt).v adjoining cathode T1. v p IIn this embodiment of my, invention theanode, oilvalve DTEis.-connected..to. the positive ppleof aqsourceiof Suit;-abledirec'tcurrent byway of lead'PA, andthe, negative pole. of.-'th'esaid direct, currentsource isconnectedtoha zero. potential common. lead.2., With anode A" of dis: charge tube- DTD'. connected. to, the.cathode, of. valve DTE,.,and.b'y way of. resistor R11 to zero potentialilat lead' Z, ,the, said :resistor. R11, forms a cathode.followed. Also. connected by, way of. leadsPA and Z'.to thede}scrihed-direct-cur rentsource, which we will :term .themainsourceoflpotential, and'inparallel. withrvalve DTE isia potential.dividing. arrangement consisting of. resistors R13; R14- and-R15, three.half-wave... rectifying valves DTA, DTB-and DTC,,andj a furtherresistor, Rl,6., Re,- sistors R13:- andmR14 are. provided with means.whereby the: potentiabat. points x..and y, respectively may be variedfor apurpose-which .will be described later. The.voltageatappingipointsxand-y are also. connected tothe gridelectrode/of;valveDIE bymeans of unsymmetrical conductive elements MR1.and MR2; resp ctively. Tapping pointsx and y are also-connectedtothezero, potential commonlead Z.by,means of decoupling capacitors, 4 and C5whichserve toensure that only thesteadyldirect current potentialdeveloped. at these, tapping, points is applied to the,grid.oi.Ivalve.DTE. Valves.DTA',,,DIB and .DTC withtheir associated:resistorRlfi formra reference-voltagesou-rceh 1 I l V y,

Each-cathode T 1 to..-T 10 in discharge tuble..DTDl is connected way;of.v a separate resistor. R40; to,1{49 respectively. to. zero.potentialiatlead Z.. Whilst each. fiIst guideaGAL to GA10 .and.secondtguide.,GBL to. CiBlOI is taken, by way of a resistor in the groups ofresistors R30 to R39 and R20 to R29 respectively, to means whereby asuitable negative-going impulse may be applied sequentially to the saidgroups of first guides and second guides. In the simple circuit depictedon the accompanying drawing such means are formed by switches SW1 andSW2 which are connected to the commoned groups of resistors R3ti-R39 andR20-R29 respectively and to direct-current sources ND and NC.

The commoned group of resistors R40-R49 associated with the cathodes T,of tube DTD are connected to the grid of valve DTE by way of capacitorC1 and resistor R17, similarly resistor groups R30-R39 and R20-R29 arealso connected to said grid by way of capacitor/resistor combinationsC2/R18 and C3/R19 respectively. The capacitor in each such combinationserves to prevent the main direct-current source from being shortcircuited by way of resistor R12.

When the pressure and content of the gaseous or other filling in thedescribed tube and valves, the spacing of the electrodes therein, andthe values of the described resistors, capacitors, and sources ofpotential are all suitable, a discharge is produced in tube DTD, and theglow thereof caused to invest cathode T1, when a pulse of suitablenegative potential is applied to the said cathode Tl. Such a pulse mayconveniently be derived by the brief application of the potential atterminal E to the point marked w. Such a discharge between anode A andcathode T1 is caused to move. and to invest cathode T2. when a pulse ofsuitable negative potential is applied sequentially to the first guidesGA and second guides GB in that order. The discharge glow is caused tomove to and invest cathode T10 however when the said sequential negativegoing pulses are applied to second guides GB and first guides GA in thatorder. Each such pair of sequential voltage impulses maybe derived froma single voltage pulse of suitable characteristics modified in knownmanner. or as in the simple arrangement shown on the accompanyingdrawing in which the sequential operation of switches SW1 and SW2 inthat order cause a negative oing pulse derived from direct currentsources ND and NC to be applied to the described groupsof first guidesGA and second guides GB.

The production of such a single discharge in tube DTD causes current ofa particular value to fiow through the tube DTD. This current is drawnfrom the main direct-current source, and its value remains substantiallyconstant re ardless of the position of the discharge in the tube DTD.When however such a discharge has been caused to move in the mannerdescribed from cathode T1, and its glow invests, for example, cathodeT4, the production of a second discharge in the tube in a similar mannerwill cause the current flowing through the tube to rise, and at the sametime will tend to lower the value of the positive potential at anode Aof the tube DTD. Each additional discharge produced in the tube DTD willhave a similar effect and will tend to lower progressively the potentialat anode A. Such changes to the value of the said potential areundesirable as they render unstable the value of the potentials which itis necessary to apply to the first and second guides GA and GB in orderto move the discharges in the tube DTD from the cathodes T on which theyare halted to other cathodes T. Thus it is desirable to maintain thepotential at anode A of the tube DTD in the region of a particular valueregardless of the number of discharges existing in the tube DTD, or ofthe positions of the electrodes invested by the discharge glows. Such avalue potential will be termed the optimum value. 1

In this present invention the potential at the anode of themulti-cathode discharge tube DTD is maintained by means of a thermionictriode DTE in the region of an optimum value at all times that the tubecontains one or more discharges. Triode DTE is arranged in acharacteristic relationship to potentials derived from a main asiaasosource of direct current, to the electrodes of the multicathodedischarge tube DTD, and to a potential dividing arrangement formed byasymmetrical elements MR1 and MR2 and resistors R13, R14, and R15 whichis connected to valves DTA, DTB and DTC, which with resistor R16 form areference voltage source. In the described arrangement of my inventionthe production of a discharge in tube DTD and the resultant flow ofcurrent through triode DTE causes a potential to be developed acrossresistor R11, and the positive potential at the electrode connected endof resistor R11 reaches a particular value. The production of anadditional dis charge in tube DTD in the manner described previously,which tends to reduce the value of the positive potential at the saidanode A of tube DTD, also tends to lower the value of the positivepotential at the cathode of triode DTE and at the adjoining end ofresistor R11. Such a tendency increases the potential difference betweenthe cathode and grid electrodes of triode DTE, and causes the currentflowing through triode DTE to increase, and in consequence the potentialdifference across the cathode follower resistor R11 returns to a valuein the region of its previous value. In this way the tendency towards alower positive potentials at the anode of tube DTD is reversed, and bychoice of suitable components in the form of triode DTE and resistor R11the potential at anode A is restored to a value which is equal, orsubstantially equal, to its previous value. This value may convenientlyform the optimum value of positive potential at which it is desirable tomaintain the anode A of tube DTD. Such a value of potential isdetermined by the potential difference across resistor R11, and isdependent upon the value of the current flowing in triode DTE. The valueof the current in triode DTE is itself dependent upon the value of thepotentials at its anode, cathode and grid electrodes. The potential atthe anode of triode DTE is fixed as it is connected directly to thepositive pole of the main direct-current source by way of lead PA. Thegrid electrode of triode DTE is held at a potential determined by thevalue of the positive potential derived from the main current source byway of resistor R12, and the potential derived from the reference.voltage source formed by valves DTA, DTB and DTC and resistor R16, inassociation with the potential dividing arrangement of resistors R13,R14, R15. The potential at the cathode of valve DTE is determined by thevalue of resistor R11, and a resistor of 100,000 ohms provides asatisfactory value of potential.

In one arrangement of the invention which has been found to besatisfactory the potential derived from the main current source is ofthe order of 400 volts, whilst the voltage of direct-current sources,NA, NC and ND is each of the order of 60 volts. The characteristics oftriode DTE are such that it functions satisfactorily when the positivepotential at the grid electrode is of the order of 250 volts, and thepositive potential at points x and y is of the order of 260 volts and240 volts respectively. With such an arrangement should the value of thepositive potential at the grid of triode DTE tend to rise above thepotential at point x current will flow through element MR1 and resistorsR13, R14 and R15, and cause the value of the potential at the gridelectrode to fall to the value of the potential at point x. Similarlyshould the value of the potential at the grid of triode DTE tend to fallbelow that at point y current will flow through element MR2 andresistors R16, R13 and R14, and cause the potential at the grid oftriode DTE to rise to the value of the potential at point y.

When a discharge has been produced in tube DTD and a discharge glow hasbeen caused to invest cathode T1 in the manner described, the subsequentapplication of a pair of suitable negative going pulses of potentialsequentially to the first guides GA and second. guides GB, in thatorder, will have the effect of moving the said discharge fromcathode T1to cathode T2- in the following manner. 0n the closure of switch SW1 thenegative potential derived from direct-current'source NC is applied toresistors R30 to R39 and thence to first guides GAl to GA10, at the sametime it is also applied to capacitor C2 and causes a negative-goingpulse of potential to be'applied tothe grid electrode of triode DTE byway of resistors R18 and R17. The application of this firstnegative-going pulse of the said pair of pulses to the grid of triodeDTE causes a reduction in the value of the current. through the saidtriode DTE with a consequent reduction in the value of the positivepotential at the anode of tube DTD. At the same time the value of thepotentialat first guides GA is made considerably more negative. Thus.conditions are pro duced in which the potential ditference between theanode A and cathode T1 in tube DTD isreduced simultaneously with anincrease in the potentialdifierence between the said anode A and firstguides GAl to GA10, and the potential difference between anode A andfirst guide GAl becomes so much greater than the potential difierencebetween the anode A andthe adjoining. cathode T1 that the dischargeceases to invest cathoderTl, and moves to and invests first guide GAl.

The second pulse of the pair of negative-going pulses is applied, by theclosure of switch SW2, to second guides GBl to GBlt) by way of resistorsR20 to R29, and to the grid of triode DTE by way of capacitor C3 andresistor R19. The second pulse is more negative than the first pulse asit is derived from direct-current sources ND and NC in series, and thenegative-going pulse at the grid of triode DTE causes a furtherreduction in. the current through the said triode DTE, and a consequentlowering of the value of the positive potential at theranode of tubeDTD. With second-guide GBl at a considerably more negative potentialthan the potential at guide GA1 conditions for the movement of thedischarge again we vail, and the discharge moves to and invests secondguide GB].. The reduction in the value of the current through triode,DTE, which occurs with the receipt of a pair of negative-going pulses ofpotential at the grid. of the said triode, is such as to cause the valueof the positive potential at the anode A of the tube DTD to fall belowthe described optimum value, and following such pulses the describedtriode valve current and tube anodepotential are restored to theirpro-pulsed values in the following manner. The application of thenegative-going pulses to the grid of triode DTE reduces the positivepotential at the said grid to a value below that of the positivepotential at point y, and current flows through asymmetrical conductingelement MR2 and causes the positive potential at the said grid to riseto a value in the region of the potential at point 3/. This increasedpositive potential at the grid of triode DTE causes the current throughthe valve to increase and to return to its pre-pulsed value.

The cessation of the pair of pulses by the opening of switches SW1-andSW2 in that order, and the con: currentincrease, inthe value of thepositive potential at the anode A of tube DTD, produces conditions inwhich, when the value of the negative potential at second guide GBlfalls below the value necessary to maintain a discharge, the potentialdifference between anode A and the adjoining cathode T2 has beenrestored to such a value that the discharge investing second-guide GBlis caused to move to and invest cathode T2.- In this way the applicationof a pair of negative-going: pulses of potential in sequence to thecommoned groups of guide electrodes GA and GB causes the discharge tomove from one cathode T to the next immediately adjacent cathode T. Atthe conclusion of such a movement the potential at the anode A of tubeDTD is restored to a value in the region of the optimum value in themanner described.

With the said discharge investing cathode T2 a second discharge may beproduced in tube DTD and caused to invest cathode T1 in a similar mannerto that described with; reference" to the =fir'st-- discharge; Such anadditional discharge causes the current'throughtube-DTD to increase,andxin consequence the-valueof the -positive potential atthe anode A of,the saidtub'e tend's=-to fall. This tendencytowards a lowervalueofiposititie potential at tube- DTDis cornmunieated to the cathode oftriode DTE; andcauses-the current through the sa-id trio-de to -increaseuntil the value of the-positive potential at the anode of-- tube DTD andthe adjoining end of resistor R11 is restored to a value in theregion-ofithe optimum value.

Whentwo=discharges have been produced in the tube DTD each I operationofiiswitches ;SW1: and SW=2tasadescribedswillica-use aapain ofnegative-going:pulsesto=be applied in sequence to: the. commoned firstguides; GA and-commoned 'secondiguides GBPzandt thedischargesiwillmove-'concurrentlyto and invest, the'next immediately adjacent cathodeT=. During eacllksuch'zcyclte :of::movement the -potential? at:the1anodeeAaof tubetDTD 'isnvariedz; in the manner-describedito.facilitate the movement-10f the discharges; but: on. completionv of:;each cycle of movements-the positive potential; at; the SB-id) anode *A.isv restored. to v a, value in the regionuof thewoptimum value. Eachadditionalsdischarge produced in tube DTDawi-ll cause; the value-1of;the current through the; said-tube to rise, andy-the value ,ofthepositiyevpotential at the anode of; the tube wilt-tend to ;=fa ll witheach zsu. :h;in :reaseof current;- but will gbe hfeld a t;,a; :valuedn;the region ;of.- the optimum value {by theautomatic-voltagestabilizing-effect ofth potential. dividing-i arrangement in,association with triode DTE: and its cathode follower circuitarrangement.- With such, an arrangement a should the-value of thepositive-potentiah at .the. gridclectrode of, triodeDTE rise-above thepredetermined-value act-potential attp oint x current will fiowtby wayof tasyrnmetrical conductingelementaMRl. and-the potentialat the triodegridiwillzb'e held. at the potential yalue-at-point x.

The describedarrangements for; guiding: a, discharge in. tube- DTD from,onecathode: T, to the; next immediatel yadjacent cathode T.- are cequally suitable for use when a, sir 1g1e discharge.. exists;in...the---tube or. when,..the maximum number. of such, dischargeshaveibeen, pro: duced therein With. such discharge guiding arrangementsthe direction in which the discharge is guided around a ring. of cathodeand guide electrodes maybeireversed by reversing the connections fromswitchies-SWland SW2 to the commoned-first guides-GA andTesistorsRSO toR39; and the commoned second guides-GB 'and resistors R20 to R29fi'Inorder 1 to maintain th'e-potential 'points x. and- 3 ataconstantgval-ueregardless of. variations: in: the :potential derived;from the; main source of direct current the potential 3dividing-resistors R13, R14- and R15 :area arranged. in parallel withthree-h alf wavevrectifyinggdiodes DTA, DTBQ andl-DTC as shown whichwith -.res istor;R16 form a,suitable..source of reference. voltagev Thearrangementby which-the potential, at tanode A of tubeDTDjs maintainedin the region .of apredetermined value when a number of discharges. in.the tube is increased to a maximum isalso satisfactory when anurnber. ofdischarges in the tube is-reduced to a minimum. Any reduction inthe'numberof'discharge s in tube DTD"automaticall'y reduces the value-ofthe-currentthrough th'e'tube; and in" consequence the value of thepositive potential 'at-anode A'tends to rise,- this voltagerisingtendency'is communicated to the cath ode of triode valve DTE, andcausesa reduction in the value of the current through triode DTE whichreduction continues until the potential 'atanode A- of tube DTD, at thecathode oftriode DTE,and'at the adjoining end of thecathodefollowerresistor R11 is stabilised at a value-inthe regionofthedescribedoptimum. With such; an arrangementfitheinvestmentofi anycathodwl may be used to develop a potential across a resistor connectedthereto, and such a potential may be applied to an output lead and forman outgoing pulse of potential. Such a resistor R2 and outgoing pulselead OP are shown connected to cathode T1. In this way a plurality ofdischarges produced in a tube DTD, in consequence of the receipt of alike number of pulses, may cause a like number of impulses to be countedout, thus the arrangement may be regarded as a means of storingimpulses.

An alternative means of producing a discharge in the multi-cathode tubeDTD between anode A and a predetermined cathode T is provided in theinvention by including switching means which are not shown on thedrawing for disconnecting the positive potential applied to anode A, andproviding at least one auxiliary electrode in the tube DTD. In one sucharrangement the discharge point of an auxiliary electrode ST is situatedin close proximity to the discharge point of the selected cathode T1,and the electrode ST is connected by way of switch SW3, terminal E, andresistor R1 to the negative pole of a source of direct-current NA. Thegap between the discharge points of electrode ST and cathode T, and thepotential derived from direct-current source NA 'are such that withswitch SW3 closed a minute discharge is produced between the saidelectrodes. Electrode ST thus acts as a so-called keep-alight electrodeand maintains the space around the discharge point of cathode T1 in anionised condition. In the absence of a potential from anode A and withthe associated switching means open, no discharge exists between anode Aand cathode T. When the said switching means are closed a positivepotential is applied to anode A, the ionised space around cathode T1facilitates the production of a discharge between the said anode A andcathode T1, and a discharge glow invests the said cathode T1. In avariation of such discharge producing means which is not shown on theaccompanying drawing, two auxiliary electrodes are provided in themulti-cathode tube and are connected by switching means to a suitablesource of direct current. The auxiliary electrode discharge points arearranged to form a small discharge gap in a position adjoining apredetermined cathode T. In the absence of a discharge between theauxiliary electrodes the potential difference between the anode and thepredetermined cathode T is insufficient to produce a discharge. When adischarge is produced between the auxiliary electrodes on the closure ofthe switching means the space around the predetermined cathode T becomesionised, and under such conditions a discharge is provided between theanode and the said cathode T.

Although the voltage stabilising arrangement has been described withreference to a single discharge tube containing a plurality of dischargepaths, its use is not confined to such tubes, and its application tomany other forms of variable load will be obvious after this simpleapplication of my invention has been understood.

What I claim is:

1. In an arrangement for counting and storing electrical pulses,comprising a gaseous electric discharge tube containing an anode and aplurality of cathodes, a direct-current source, the positive potentialof which is applied to said anode, means for applying at least one pulseto one of said cathodes and storing the pulse within the discharge tubein the form of a discharge between said anode and said last namedcathode, and means for applying a varying number of pulses to a varyingnumber of said cathodes in common and thereby causing a varying numberof discharges to move from one group of said cathodes to another groupof said cathodes, thereby varying the load in said discharge tube; theimproveinent of stabilizing means for maintaining automatically thevalue of the potential at said anode of said discharge tube stablewithin a determined range of values regardless of changes in the numberof discharges in said discharge tube.

2. In an arrangement for counting and storing electrical pulses,comprising a gaseous electric discharge tube containing an anode and aplurality of cathodes, a directcurrent source, the positive potential ofwhich is applied to said anode, means for applying at least one pulse toone of said cathodes and storing the pulse within the discharge tube inthe form of a discharge between said anode and said last named cathode,and means for applying a varying number of pulses to a varying number ofsaid cathodes in common and thereby causing a varying number ofdischarges to move from one group of said cathodes to another group ofsaid cathodes, thereby varying the load in said discharge tube; theimprovement of stabilizing means for maintaining automatically the valueof the potential at said anode of said discharge tube stable within adetermined range of values regardless of changes in the number ofdischarges in said discharge tube, said stabilizing means comprising athermionic valve having anode means, cathode means and grid meanstherein, a cathode follower circuit associated with said thermionicvalve and a reference voltage source connected in parallel with saidthermionic valve to said direct current source, said anode means of saidthermionic valve being connected to the positive potential of saiddirect-current source, said cathode means being connected to said anodeof said discharge tube as well as to said cathode follower circuit, andsaid grid means being connected to said reference voltage source.

3. In an arrangement for counting and storing electrical pulses, theimprovement described in claim 2 in which potentials derived from saidreference voltage source are applied by way of unsymmetrical conductiveelements to said grid means of said thermionic valve and are adapted tomaintain automatically the potential at said grid means within adetermined range or" values.

4. In an arrangement for counting and storing electrical pulses, theimprovement described in claim 2, in which said reference voltage sourceincludes a plurality of diodes in series and a voltage divider inparallel with said diodes.

5. Voltage stabilizing arrangements according to claim 2 wherein saidgrid means of said thermionic valve is coupled to said reference voltagesource by at least two unsymmetrical conductive elements whereby apotential applied to said grid means is maintained automatically at avalue within a determined range of values.

6. In an arrangement for counting and storing electrical pulses,comprising a gaseous electric discharge tube containing an anode and aplurality of cathodes, a direct-current source, the positive potentialof which is applied to said anode, means for applying at least one pulseto one of said cathodes and storing the pulse within the discharge tubein the form of a discharge between said anode and last last namedcathode, means whereby a pulse stored in said discharge tube in the formof a discharge is counted out from said tube in pulse form, and meansfor applying a varying number of pulses to a varying number of saidcathodes in common and thereby causing a varying number of discharges tomove from one group of said cathodes to another group of said cathodes,thereby varying the load in said discharge tube; the improvement ofstabilizing means for maintaining automatically the value of thepotential at said anode of said discharge tube stable within adetermined range of values regardless of changes in the number ofdischarges in said discharge tube, said stabilizing means comprising athermionic valve having anode m ans, cathode means and grid meanstherein, a cathode follower circuit associated with said thermionicvalve and a reference voltage source connected in parallel with saidthermionic valve to said direct current'source, said anode means of saidthermionic valve being connected to the positive potential of saiddirect-current source, said cathode means being connected to said anodeof said discharge tube as well as to said cathode follower circuit, andsaid grid means being connected to said reference voltage source.

References Cited in the file of this patent UNITED STATES PATENTSPhilpott Feb. 14, 1938 Trevor July 6, 1943 Levy Jan. 27, 1948 MentzerOct. 3, 1950 Acton Sept. 1, 1953 Nelson Dec. 6, 1955

